I use DoPDF, CutePDF and another I don't recall. My bet is that your title came with the printer so you'll have to ask Canon what's up.
I use Win7 and a Brother DCP multi-function copier with MS Office 2002. Can't recall ever downloading PDF Complete but it allows me to print to PDF from various displayed documents. Until today, when it announced that "Your complimentary use period has ended." Acrobat Reader X is kept current-ish, but is there an update for PDF Complete?